Wafers are processed in many ways, some of which are done in a process chamber of a wafer processing tool. In stages of wafer processing, including, for example, pre-cleaning, post-cleaning, or etching, chemical materials are added to a surface of the wafer to form or modify layers of material on the surface. To accelerate chemical reactions for the process, the wafer often needs to be heated to a suitable temperature. To keep reliability of the wafers, temperature control of the wafers is employed during the stages of wafer processing.